diff --git a/pyproject.toml b/pyproject.toml
index 3bd3f73f..2714d288 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -33,10 +33,10 @@ tomli = { version = "*", markers = "extra == 'toml' or extra == 'all'", optional
 tomli-w = { version = "*", markers = "extra == 'toml' or extra == 'all'", optional = true }
 pyyaml = { version = "*", markers = "extra == 'yaml' or extra == 'all'", optional = true }
 numpy = [
-    { version = ">1.21.0", markers = "python_version ~= '3.9.0' and (extra == 'numpy' or extra == 'all')", optional = true },
-    { version = ">1.22.0", markers = "python_version ~= '3.10' and (extra == 'numpy' or extra == 'all')", optional = true },
-    { version = ">1.22.0", markers = "python_version ~= '3.11' and (extra == 'numpy' or extra == 'all')", optional = true },
-    { version = ">1.22.0", markers = "python_version ~= '3.12' and (extra == 'numpy' or extra == 'all')", optional = true },
+    { version = ">1.21.0,<2.0.0", markers = "python_version ~= '3.9.0' and (extra == 'numpy' or extra == 'all')", optional = true },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.10' and (extra == 'numpy' or extra == 'all')", optional = true },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.11' and (extra == 'numpy' or extra == 'all')", optional = true },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.12' and (extra == 'numpy' or extra == 'all')", optional = true },
 ]
 orjson = { version = "*", markers = "extra == 'orjson' or extra == 'all'", optional = true }
 plum-dispatch = ">=2,<2.3"
@@ -49,10 +49,10 @@ tomli = { version = "*", markers = "python_version <= '3.11.0'" }
 tomli-w = "*"
 msgpack = "*"
 numpy = [
-    { version = ">1.21.0", markers = "python_version ~= '3.9.0'" },
-    { version = ">1.22.0", markers = "python_version ~= '3.10'" },
-    { version = ">1.22.0", markers = "python_version ~= '3.11'" },
-    { version = ">1.22.0", markers = "python_version ~= '3.12'" },
+    { version = ">1.21.0,<2.0.0", markers = "python_version ~= '3.9.0'" },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.10'" },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.11'" },
+    { version = ">1.22.0,<2.0.0", markers = "python_version ~= '3.12'" },
 ]
 mypy = "==1.10.0"
 pytest = "*"